1. Field of the Invention
The invention relates to a timepiece, in particular a wristwatch, having a casing with an interior which has, on the viewer's side, an opening closed by a cover glass and, on the base side, a sound aperture which is closed by a membrane having a circumferential region in sealed connection with a corresponding annular surface of the casing. A vibration generator arranged in the casing interior can generate sound vibrations.
2. Description of the Related Art
In the case of such timepieces, the membrane ensures that the casing interior, in which the movement and the vibration generator are located, is closed in the outward direction in order to prevent the ingress of dirt and moisture.
At the same time, the ability of the membrane to vibrate is intended to ensure good transmission in the outward direction of the sound vibrations generated by the vibration generator.
However, this transmission of the sound vibrations in the outward direction only takes place optimally when the frequency of the sound vibrations generated by the vibration generator and the characteristic frequency of the membrane are equal.